1 // Copyright 2015 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 // This header file defines the set of trace_event macros without specifying
6 // how the events actually get collected and stored. If you need to expose trace
7 // events to some other universe, you can copy-and-paste this file as well as
8 // trace_event.h, modifying the macros contained there as necessary for the
9 // target platform. The end result is that multiple libraries can funnel events
10 // through to a shared trace event collector.
11 
12 // IMPORTANT: To avoid conflicts, if you need to modify this file for a library,
13 // land your change in base/ first, and then copy-and-paste it.
14 
15 // Trace events are for tracking application performance and resource usage.
16 // Macros are provided to track:
17 //    Begin and end of function calls
18 //    Counters
19 //
20 // Events are issued against categories. Whereas LOG's
21 // categories are statically defined, TRACE categories are created
22 // implicitly with a string. For example:
23 //   TRACE_EVENT_INSTANT0("MY_SUBSYSTEM", "SomeImportantEvent",
24 //                        TRACE_EVENT_SCOPE_THREAD)
25 //
26 // It is often the case that one trace may belong in multiple categories at the
27 // same time. The first argument to the trace can be a comma-separated list of
28 // categories, forming a category group, like:
29 //
30 // TRACE_EVENT_INSTANT0("input,views", "OnMouseOver", TRACE_EVENT_SCOPE_THREAD)
31 //
32 // We can enable/disable tracing of OnMouseOver by enabling/disabling either
33 // category.
34 //
35 // Events can be INSTANT, or can be pairs of BEGIN and END in the same scope:
36 //   TRACE_EVENT_BEGIN0("MY_SUBSYSTEM", "SomethingCostly")
37 //   doSomethingCostly()
38 //   TRACE_EVENT_END0("MY_SUBSYSTEM", "SomethingCostly")
39 // Note: our tools can't always determine the correct BEGIN/END pairs unless
40 // these are used in the same scope. Use ASYNC_BEGIN/ASYNC_END macros if you
41 // need them to be in separate scopes.
42 //
43 // A common use case is to trace entire function scopes. This
44 // issues a trace BEGIN and END automatically:
45 //   void doSomethingCostly() {
46 //     TRACE_EVENT0("MY_SUBSYSTEM", "doSomethingCostly");
47 //     ...
48 //   }
49 //
50 // Additional parameters can be associated with an event:
51 //   void doSomethingCostly2(int howMuch) {
52 //     TRACE_EVENT1("MY_SUBSYSTEM", "doSomethingCostly",
53 //         "howMuch", howMuch);
54 //     ...
55 //   }
56 //
57 // The trace system will automatically add to this information the
58 // current process id, thread id, and a timestamp in microseconds.
59 //
60 // To trace an asynchronous procedure such as an IPC send/receive, use
61 // ASYNC_BEGIN and ASYNC_END:
62 //   [single threaded sender code]
63 //     static int send_count = 0;
64 //     ++send_count;
65 //     TRACE_EVENT_ASYNC_BEGIN0("ipc", "message", send_count);
66 //     Send(new MyMessage(send_count));
67 //   [receive code]
68 //     void OnMyMessage(send_count) {
69 //       TRACE_EVENT_ASYNC_END0("ipc", "message", send_count);
70 //     }
71 // The third parameter is a unique ID to match ASYNC_BEGIN/ASYNC_END pairs.
72 // ASYNC_BEGIN and ASYNC_END can occur on any thread of any traced process.
73 // Pointers can be used for the ID parameter, and they will be mangled
74 // internally so that the same pointer on two different processes will not
75 // match. For example:
76 //   class MyTracedClass {
77 //    public:
78 //     MyTracedClass() {
79 //       TRACE_EVENT_ASYNC_BEGIN0("category", "MyTracedClass", this);
80 //     }
81 //     ~MyTracedClass() {
82 //       TRACE_EVENT_ASYNC_END0("category", "MyTracedClass", this);
83 //     }
84 //   }
85 //
86 // Trace event also supports counters, which is a way to track a quantity
87 // as it varies over time. Counters are created with the following macro:
88 //   TRACE_COUNTER1("MY_SUBSYSTEM", "myCounter", g_myCounterValue);
89 //
90 // Counters are process-specific. The macro itself can be issued from any
91 // thread, however.
92 //
93 // Sometimes, you want to track two counters at once. You can do this with two
94 // counter macros:
95 //   TRACE_COUNTER1("MY_SUBSYSTEM", "myCounter0", g_myCounterValue[0]);
96 //   TRACE_COUNTER1("MY_SUBSYSTEM", "myCounter1", g_myCounterValue[1]);
97 // Or you can do it with a combined macro:
98 //   TRACE_COUNTER2("MY_SUBSYSTEM", "myCounter",
99 //       "bytesPinned", g_myCounterValue[0],
100 //       "bytesAllocated", g_myCounterValue[1]);
101 // This indicates to the tracing UI that these counters should be displayed
102 // in a single graph, as a summed area chart.
103 //
104 // Since counters are in a global namespace, you may want to disambiguate with a
105 // unique ID, by using the TRACE_COUNTER_ID* variations.
106 //
107 // By default, trace collection is compiled in, but turned off at runtime.
108 // Collecting trace data is the responsibility of the embedding
109 // application. In Chrome's case, navigating to about:tracing will turn on
110 // tracing and display data collected across all active processes.
111 //
112 //
113 // Memory scoping note:
114 // Tracing copies the pointers, not the string content, of the strings passed
115 // in for category_group, name, and arg_names.  Thus, the following code will
116 // cause problems:
117 //     char* str = strdup("importantName");
118 //     TRACE_EVENT_INSTANT0("SUBSYSTEM", str);  // BAD!
119 //     free(str);                   // Trace system now has dangling pointer
120 //
121 // To avoid this issue with the |name| and |arg_name| parameters, use the
122 // TRACE_EVENT_COPY_XXX overloads of the macros at additional runtime overhead.
123 // Notes: The category must always be in a long-lived char* (i.e. static const).
124 //        The |arg_values|, when used, are always deep copied with the _COPY
125 //        macros.
126 //
127 // When are string argument values copied:
128 // const char* arg_values are only referenced by default:
129 //     TRACE_EVENT1("category", "name",
130 //                  "arg1", "literal string is only referenced");
131 // Use TRACE_STR_COPY to force copying of a const char*:
132 //     TRACE_EVENT1("category", "name",
133 //                  "arg1", TRACE_STR_COPY("string will be copied"));
134 // std::string arg_values are always copied:
135 //     TRACE_EVENT1("category", "name",
136 //                  "arg1", std::string("string will be copied"));
137 //
138 //
139 // Convertable notes:
140 // Converting a large data type to a string can be costly. To help with this,
141 // the trace framework provides an interface ConvertableToTraceFormat. If you
142 // inherit from it and implement the AppendAsTraceFormat method the trace
143 // framework will call back to your object to convert a trace output time. This
144 // means, if the category for the event is disabled, the conversion will not
145 // happen.
146 //
147 //   class MyData : public base::trace_event::ConvertableToTraceFormat {
148 //    public:
149 //     MyData() {}
150 //     void AppendAsTraceFormat(std::string* out) const override {
151 //       out->append("{\"foo\":1}");
152 //     }
153 //    private:
154 //     ~MyData() override {}
155 //     DISALLOW_COPY_AND_ASSIGN(MyData);
156 //   };
157 //
158 //   TRACE_EVENT1("foo", "bar", "data",
159 //                scoped_refptr<ConvertableToTraceFormat>(new MyData()));
160 //
161 // The trace framework will take ownership if the passed pointer and it will
162 // be free'd when the trace buffer is flushed.
163 //
164 // Note, we only do the conversion when the buffer is flushed, so the provided
165 // data object should not be modified after it's passed to the trace framework.
166 //
167 //
168 // Thread Safety:
169 // A thread safe singleton and mutex are used for thread safety. Category
170 // enabled flags are used to limit the performance impact when the system
171 // is not enabled.
172 //
173 // TRACE_EVENT macros first cache a pointer to a category. The categories are
174 // statically allocated and safe at all times, even after exit. Fetching a
175 // category is protected by the TraceLog::lock_. Multiple threads initializing
176 // the static variable is safe, as they will be serialized by the lock and
177 // multiple calls will return the same pointer to the category.
178 //
179 // Then the category_group_enabled flag is checked. This is a unsigned char, and
180 // not intended to be multithread safe. It optimizes access to AddTraceEvent
181 // which is threadsafe internally via TraceLog::lock_. The enabled flag may
182 // cause some threads to incorrectly call or skip calling AddTraceEvent near
183 // the time of the system being enabled or disabled. This is acceptable as
184 // we tolerate some data loss while the system is being enabled/disabled and
185 // because AddTraceEvent is threadsafe internally and checks the enabled state
186 // again under lock.
187 //
188 // Without the use of these static category pointers and enabled flags all
189 // trace points would carry a significant performance cost of acquiring a lock
190 // and resolving the category.
191 
192 #if defined(TRACE_EVENT0)
193 #error "Another copy of this file has already been included."
194 #endif
195 
196 // This will mark the trace event as disabled by default. The user will need
197 // to explicitly enable the event.
198 #define TRACE_DISABLED_BY_DEFAULT(name) "disabled-by-default-" name
199 
200 // Records a pair of begin and end events called "name" for the current
201 // scope, with 0, 1 or 2 associated arguments. If the category is not
202 // enabled, then this does nothing.
203 // - category and name strings must have application lifetime (statics or
204 //   literals). They may not include " chars.
205 #define TRACE_EVENT0(category_group, name)    \
206   INTERNAL_TRACE_EVENT_ADD_SCOPED(category_group, name)
207 #define TRACE_EVENT_WITH_FLOW0(category_group, name, bind_id, flow_flags)  \
208   INTERNAL_TRACE_EVENT_ADD_SCOPED_WITH_FLOW(category_group, name, bind_id, \
209                                             flow_flags)
210 #define TRACE_EVENT1(category_group, name, arg1_name, arg1_val) \
211   INTERNAL_TRACE_EVENT_ADD_SCOPED(category_group, name, arg1_name, arg1_val)
212 #define TRACE_EVENT_WITH_FLOW1(category_group, name, bind_id, flow_flags,  \
213                                arg1_name, arg1_val)                        \
214   INTERNAL_TRACE_EVENT_ADD_SCOPED_WITH_FLOW(category_group, name, bind_id, \
215                                             flow_flags, arg1_name, arg1_val)
216 #define TRACE_EVENT2(category_group, name, arg1_name, arg1_val, arg2_name,   \
217                      arg2_val)                                               \
218   INTERNAL_TRACE_EVENT_ADD_SCOPED(category_group, name, arg1_name, arg1_val, \
219                                   arg2_name, arg2_val)
220 #define TRACE_EVENT_WITH_FLOW2(category_group, name, bind_id, flow_flags,    \
221                                arg1_name, arg1_val, arg2_name, arg2_val)     \
222   INTERNAL_TRACE_EVENT_ADD_SCOPED_WITH_FLOW(category_group, name, bind_id,   \
223                                             flow_flags, arg1_name, arg1_val, \
224                                             arg2_name, arg2_val)
225 
226 // UNSHIPPED_TRACE_EVENT* are like TRACE_EVENT* except that they are not
227 // included in official builds.
228 
229 #if OFFICIAL_BUILD
230 #undef TRACING_IS_OFFICIAL_BUILD
231 #define TRACING_IS_OFFICIAL_BUILD 1
232 #elif !defined(TRACING_IS_OFFICIAL_BUILD)
233 #define TRACING_IS_OFFICIAL_BUILD 0
234 #endif
235 
236 #if TRACING_IS_OFFICIAL_BUILD
237 #define UNSHIPPED_TRACE_EVENT0(category_group, name) (void)0
238 #define UNSHIPPED_TRACE_EVENT1(category_group, name, arg1_name, arg1_val) \
239   (void)0
240 #define UNSHIPPED_TRACE_EVENT2(category_group, name, arg1_name, arg1_val, \
241                                arg2_name, arg2_val)                       \
242   (void)0
243 #define UNSHIPPED_TRACE_EVENT_INSTANT0(category_group, name, scope) (void)0
244 #define UNSHIPPED_TRACE_EVENT_INSTANT1(category_group, name, scope, arg1_name, \
245                                        arg1_val)                               \
246   (void)0
247 #define UNSHIPPED_TRACE_EVENT_INSTANT2(category_group, name, scope, arg1_name, \
248                                        arg1_val, arg2_name, arg2_val)          \
249   (void)0
250 #else
251 #define UNSHIPPED_TRACE_EVENT0(category_group, name) \
252   TRACE_EVENT0(category_group, name)
253 #define UNSHIPPED_TRACE_EVENT1(category_group, name, arg1_name, arg1_val) \
254   TRACE_EVENT1(category_group, name, arg1_name, arg1_val)
255 #define UNSHIPPED_TRACE_EVENT2(category_group, name, arg1_name, arg1_val, \
256                                arg2_name, arg2_val)                       \
257   TRACE_EVENT2(category_group, name, arg1_name, arg1_val, arg2_name, arg2_val)
258 #define UNSHIPPED_TRACE_EVENT_INSTANT0(category_group, name, scope) \
259   TRACE_EVENT_INSTANT0(category_group, name, scope)
260 #define UNSHIPPED_TRACE_EVENT_INSTANT1(category_group, name, scope, arg1_name, \
261                                        arg1_val)                               \
262   TRACE_EVENT_INSTANT1(category_group, name, scope, arg1_name, arg1_val)
263 #define UNSHIPPED_TRACE_EVENT_INSTANT2(category_group, name, scope, arg1_name, \
264                                        arg1_val, arg2_name, arg2_val)          \
265   TRACE_EVENT_INSTANT2(category_group, name, scope, arg1_name, arg1_val,       \
266                        arg2_name, arg2_val)
267 #endif
268 
269 // Records a single event called "name" immediately, with 0, 1 or 2
270 // associated arguments. If the category is not enabled, then this
271 // does nothing.
272 // - category and name strings must have application lifetime (statics or
273 //   literals). They may not include " chars.
274 #define TRACE_EVENT_INSTANT0(category_group, name, scope)                   \
275   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_INSTANT, category_group, name, \
276                            TRACE_EVENT_FLAG_NONE | scope)
277 #define TRACE_EVENT_INSTANT1(category_group, name, scope, arg1_name, arg1_val) \
278   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_INSTANT, category_group, name,    \
279                            TRACE_EVENT_FLAG_NONE | scope, arg1_name, arg1_val)
280 #define TRACE_EVENT_INSTANT2(category_group, name, scope, arg1_name, arg1_val, \
281                              arg2_name, arg2_val)                              \
282   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_INSTANT, category_group, name,    \
283                            TRACE_EVENT_FLAG_NONE | scope, arg1_name, arg1_val, \
284                            arg2_name, arg2_val)
285 #define TRACE_EVENT_COPY_INSTANT0(category_group, name, scope)              \
286   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_INSTANT, category_group, name, \
287                            TRACE_EVENT_FLAG_COPY | scope)
288 #define TRACE_EVENT_COPY_INSTANT1(category_group, name, scope, arg1_name,   \
289                                   arg1_val)                                 \
290   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_INSTANT, category_group, name, \
291                            TRACE_EVENT_FLAG_COPY | scope, arg1_name, arg1_val)
292 #define TRACE_EVENT_COPY_INSTANT2(category_group, name, scope, arg1_name,      \
293                                   arg1_val, arg2_name, arg2_val)               \
294   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_INSTANT, category_group, name,    \
295                            TRACE_EVENT_FLAG_COPY | scope, arg1_name, arg1_val, \
296                            arg2_name, arg2_val)
297 
298 #define TRACE_EVENT_INSTANT_WITH_TIMESTAMP0(category_group, name, scope, \
299                                             timestamp)                   \
300   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                    \
301       TRACE_EVENT_PHASE_INSTANT, category_group, name, 0, 0, timestamp,  \
302       TRACE_EVENT_FLAG_NONE | scope)
303 
304 // Syntactic sugars for the sampling tracing in the main thread.
305 #define TRACE_EVENT_SCOPED_SAMPLING_STATE(category, name) \
306   TRACE_EVENT_SCOPED_SAMPLING_STATE_FOR_BUCKET(0, category, name)
307 #define TRACE_EVENT_GET_SAMPLING_STATE() \
308   TRACE_EVENT_GET_SAMPLING_STATE_FOR_BUCKET(0)
309 #define TRACE_EVENT_SET_SAMPLING_STATE(category, name) \
310   TRACE_EVENT_SET_SAMPLING_STATE_FOR_BUCKET(0, category, name)
311 #define TRACE_EVENT_SET_NONCONST_SAMPLING_STATE(categoryAndName) \
312   TRACE_EVENT_SET_NONCONST_SAMPLING_STATE_FOR_BUCKET(0, categoryAndName)
313 
314 // Records a single BEGIN event called "name" immediately, with 0, 1 or 2
315 // associated arguments. If the category is not enabled, then this
316 // does nothing.
317 // - category and name strings must have application lifetime (statics or
318 //   literals). They may not include " chars.
319 #define TRACE_EVENT_BEGIN0(category_group, name)                          \
320   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_BEGIN, category_group, name, \
321                            TRACE_EVENT_FLAG_NONE)
322 #define TRACE_EVENT_BEGIN1(category_group, name, arg1_name, arg1_val)     \
323   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_BEGIN, category_group, name, \
324                            TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
325 #define TRACE_EVENT_BEGIN2(category_group, name, arg1_name, arg1_val,     \
326                            arg2_name, arg2_val)                           \
327   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_BEGIN, category_group, name, \
328                            TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val,    \
329                            arg2_name, arg2_val)
330 #define TRACE_EVENT_COPY_BEGIN0(category_group, name)                     \
331   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_BEGIN, category_group, name, \
332                            TRACE_EVENT_FLAG_COPY)
333 #define TRACE_EVENT_COPY_BEGIN1(category_group, name, arg1_name, arg1_val) \
334   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_BEGIN, category_group, name,  \
335                            TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val)
336 #define TRACE_EVENT_COPY_BEGIN2(category_group, name, arg1_name, arg1_val, \
337                                 arg2_name, arg2_val)                       \
338   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_BEGIN, category_group, name,  \
339                            TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val,     \
340                            arg2_name, arg2_val)
341 
342 // Similar to TRACE_EVENT_BEGINx but with a custom |at| timestamp provided.
343 // - |id| is used to match the _BEGIN event with the _END event.
344 //   Events are considered to match if their category_group, name and id values
345 //   all match. |id| must either be a pointer or an integer value up to 64 bits.
346 //   If it's a pointer, the bits will be xored with a hash of the process ID so
347 //   that the same pointer on two different processes will not collide.
348 #define TRACE_EVENT_BEGIN_WITH_ID_TID_AND_TIMESTAMP0(category_group, name, id, \
349                                                      thread_id, timestamp)     \
350   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                          \
351       TRACE_EVENT_PHASE_ASYNC_BEGIN, category_group, name, id, thread_id,      \
352       timestamp, TRACE_EVENT_FLAG_NONE)
353 #define TRACE_EVENT_COPY_BEGIN_WITH_ID_TID_AND_TIMESTAMP0(                \
354     category_group, name, id, thread_id, timestamp)                       \
355   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                     \
356       TRACE_EVENT_PHASE_ASYNC_BEGIN, category_group, name, id, thread_id, \
357       timestamp, TRACE_EVENT_FLAG_COPY)
358 #define TRACE_EVENT_COPY_BEGIN_WITH_ID_TID_AND_TIMESTAMP1(                \
359     category_group, name, id, thread_id, timestamp, arg1_name, arg1_val)  \
360   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                     \
361       TRACE_EVENT_PHASE_ASYNC_BEGIN, category_group, name, id, thread_id, \
362       timestamp, TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val)
363 #define TRACE_EVENT_COPY_BEGIN_WITH_ID_TID_AND_TIMESTAMP2(                \
364     category_group, name, id, thread_id, timestamp, arg1_name, arg1_val,  \
365     arg2_name, arg2_val)                                                  \
366   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                     \
367       TRACE_EVENT_PHASE_ASYNC_BEGIN, category_group, name, id, thread_id, \
368       timestamp, TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val, arg2_name,   \
369       arg2_val)
370 
371 // Records a single END event for "name" immediately. If the category
372 // is not enabled, then this does nothing.
373 // - category and name strings must have application lifetime (statics or
374 //   literals). They may not include " chars.
375 #define TRACE_EVENT_END0(category_group, name)                          \
376   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_END, category_group, name, \
377                            TRACE_EVENT_FLAG_NONE)
378 #define TRACE_EVENT_END1(category_group, name, arg1_name, arg1_val)     \
379   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_END, category_group, name, \
380                            TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
381 #define TRACE_EVENT_END2(category_group, name, arg1_name, arg1_val, arg2_name, \
382                          arg2_val)                                             \
383   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_END, category_group, name,        \
384                            TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val,         \
385                            arg2_name, arg2_val)
386 #define TRACE_EVENT_COPY_END0(category_group, name)                     \
387   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_END, category_group, name, \
388                            TRACE_EVENT_FLAG_COPY)
389 #define TRACE_EVENT_COPY_END1(category_group, name, arg1_name, arg1_val) \
390   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_END, category_group, name,  \
391                            TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val)
392 #define TRACE_EVENT_COPY_END2(category_group, name, arg1_name, arg1_val, \
393                               arg2_name, arg2_val)                       \
394   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_END, category_group, name,  \
395                            TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val,   \
396                            arg2_name, arg2_val)
397 
398 #define TRACE_EVENT_MARK_WITH_TIMESTAMP1(category_group, name, timestamp, \
399                                          arg1_name, arg1_val)             \
400   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                     \
401       TRACE_EVENT_PHASE_MARK, category_group, name, 0, 0, timestamp,      \
402       TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
403 
404 #define TRACE_EVENT_COPY_MARK(category_group, name)                      \
405   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_MARK, category_group, name, \
406                            TRACE_EVENT_FLAG_COPY)
407 
408 #define TRACE_EVENT_COPY_MARK_WITH_TIMESTAMP(category_group, name, timestamp) \
409   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                         \
410       TRACE_EVENT_PHASE_MARK, category_group, name, 0, 0, timestamp,          \
411       TRACE_EVENT_FLAG_COPY)
412 
413 // Similar to TRACE_EVENT_ENDx but with a custom |at| timestamp provided.
414 // - |id| is used to match the _BEGIN event with the _END event.
415 //   Events are considered to match if their category_group, name and id values
416 //   all match. |id| must either be a pointer or an integer value up to 64 bits.
417 //   If it's a pointer, the bits will be xored with a hash of the process ID so
418 //   that the same pointer on two different processes will not collide.
419 #define TRACE_EVENT_END_WITH_ID_TID_AND_TIMESTAMP0(category_group, name, id, \
420                                                    thread_id, timestamp)     \
421   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                        \
422       TRACE_EVENT_PHASE_ASYNC_END, category_group, name, id, thread_id,      \
423       timestamp, TRACE_EVENT_FLAG_NONE)
424 #define TRACE_EVENT_COPY_END_WITH_ID_TID_AND_TIMESTAMP0(                \
425     category_group, name, id, thread_id, timestamp)                     \
426   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                   \
427       TRACE_EVENT_PHASE_ASYNC_END, category_group, name, id, thread_id, \
428       timestamp, TRACE_EVENT_FLAG_COPY)
429 #define TRACE_EVENT_COPY_END_WITH_ID_TID_AND_TIMESTAMP1(                 \
430     category_group, name, id, thread_id, timestamp, arg1_name, arg1_val) \
431   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                    \
432       TRACE_EVENT_PHASE_ASYNC_END, category_group, name, id, thread_id,  \
433       timestamp, TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val)
434 #define TRACE_EVENT_COPY_END_WITH_ID_TID_AND_TIMESTAMP2(                 \
435     category_group, name, id, thread_id, timestamp, arg1_name, arg1_val, \
436     arg2_name, arg2_val)                                                 \
437   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                    \
438       TRACE_EVENT_PHASE_ASYNC_END, category_group, name, id, thread_id,  \
439       timestamp, TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val, arg2_name,  \
440       arg2_val)
441 
442 // Records the value of a counter called "name" immediately. Value
443 // must be representable as a 32 bit integer.
444 // - category and name strings must have application lifetime (statics or
445 //   literals). They may not include " chars.
446 #define TRACE_COUNTER1(category_group, name, value)                         \
447   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_COUNTER, category_group, name, \
448                            TRACE_EVENT_FLAG_NONE, "value",                  \
449                            static_cast<int>(value))
450 #define TRACE_COPY_COUNTER1(category_group, name, value)                    \
451   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_COUNTER, category_group, name, \
452                            TRACE_EVENT_FLAG_COPY, "value",                  \
453                            static_cast<int>(value))
454 
455 // Records the values of a multi-parted counter called "name" immediately.
456 // The UI will treat value1 and value2 as parts of a whole, displaying their
457 // values as a stacked-bar chart.
458 // - category and name strings must have application lifetime (statics or
459 //   literals). They may not include " chars.
460 #define TRACE_COUNTER2(category_group, name, value1_name, value1_val,       \
461                        value2_name, value2_val)                             \
462   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_COUNTER, category_group, name, \
463                            TRACE_EVENT_FLAG_NONE, value1_name,              \
464                            static_cast<int>(value1_val), value2_name,       \
465                            static_cast<int>(value2_val))
466 #define TRACE_COPY_COUNTER2(category_group, name, value1_name, value1_val,  \
467                             value2_name, value2_val)                        \
468   INTERNAL_TRACE_EVENT_ADD(TRACE_EVENT_PHASE_COUNTER, category_group, name, \
469                            TRACE_EVENT_FLAG_COPY, value1_name,              \
470                            static_cast<int>(value1_val), value2_name,       \
471                            static_cast<int>(value2_val))
472 
473 // Similar to TRACE_COUNTERx, but with a custom |timestamp| provided.
474 #define TRACE_COUNTER_WITH_TIMESTAMP1(category_group, name, timestamp, value) \
475   INTERNAL_TRACE_EVENT_ADD_WITH_TIMESTAMP(                                    \
476       TRACE_EVENT_PHASE_COUNTER, category_group, name, timestamp,             \
477       TRACE_EVENT_FLAG_NONE, "value", static_cast<int>(value))
478 
479 #define TRACE_COUNTER_WITH_TIMESTAMP2(category_group, name, timestamp,      \
480                                       value1_name, value1_val, value2_name, \
481                                       value2_val)                           \
482   INTERNAL_TRACE_EVENT_ADD_WITH_TIMESTAMP(                                  \
483       TRACE_EVENT_PHASE_COUNTER, category_group, name, timestamp,           \
484       TRACE_EVENT_FLAG_NONE, value1_name, static_cast<int>(value1_val),     \
485       value2_name, static_cast<int>(value2_val))
486 
487 // Records the value of a counter called "name" immediately. Value
488 // must be representable as a 32 bit integer.
489 // - category and name strings must have application lifetime (statics or
490 //   literals). They may not include " chars.
491 // - |id| is used to disambiguate counters with the same name. It must either
492 //   be a pointer or an integer value up to 64 bits. If it's a pointer, the bits
493 //   will be xored with a hash of the process ID so that the same pointer on
494 //   two different processes will not collide.
495 #define TRACE_COUNTER_ID1(category_group, name, id, value)                    \
496   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_COUNTER, category_group, \
497                                    name, id, TRACE_EVENT_FLAG_NONE, "value",  \
498                                    static_cast<int>(value))
499 #define TRACE_COPY_COUNTER_ID1(category_group, name, id, value)               \
500   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_COUNTER, category_group, \
501                                    name, id, TRACE_EVENT_FLAG_COPY, "value",  \
502                                    static_cast<int>(value))
503 
504 // Records the values of a multi-parted counter called "name" immediately.
505 // The UI will treat value1 and value2 as parts of a whole, displaying their
506 // values as a stacked-bar chart.
507 // - category and name strings must have application lifetime (statics or
508 //   literals). They may not include " chars.
509 // - |id| is used to disambiguate counters with the same name. It must either
510 //   be a pointer or an integer value up to 64 bits. If it's a pointer, the bits
511 //   will be xored with a hash of the process ID so that the same pointer on
512 //   two different processes will not collide.
513 #define TRACE_COUNTER_ID2(category_group, name, id, value1_name, value1_val,  \
514                           value2_name, value2_val)                            \
515   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_COUNTER, category_group, \
516                                    name, id, TRACE_EVENT_FLAG_NONE,           \
517                                    value1_name, static_cast<int>(value1_val), \
518                                    value2_name, static_cast<int>(value2_val))
519 #define TRACE_COPY_COUNTER_ID2(category_group, name, id, value1_name,         \
520                                value1_val, value2_name, value2_val)           \
521   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_COUNTER, category_group, \
522                                    name, id, TRACE_EVENT_FLAG_COPY,           \
523                                    value1_name, static_cast<int>(value1_val), \
524                                    value2_name, static_cast<int>(value2_val))
525 
526 // TRACE_EVENT_SAMPLE_* events are injected by the sampling profiler.
527 #define TRACE_EVENT_SAMPLE_WITH_TID_AND_TIMESTAMP0(category_group, name,       \
528                                                    thread_id, timestamp)       \
529   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                          \
530       TRACE_EVENT_PHASE_SAMPLE, category_group, name, 0, thread_id, timestamp, \
531       TRACE_EVENT_FLAG_NONE)
532 
533 #define TRACE_EVENT_SAMPLE_WITH_TID_AND_TIMESTAMP1(                            \
534     category_group, name, thread_id, timestamp, arg1_name, arg1_val)           \
535   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                          \
536       TRACE_EVENT_PHASE_SAMPLE, category_group, name, 0, thread_id, timestamp, \
537       TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
538 
539 #define TRACE_EVENT_SAMPLE_WITH_TID_AND_TIMESTAMP2(category_group, name,       \
540                                                    thread_id, timestamp,       \
541                                                    arg1_name, arg1_val,        \
542                                                    arg2_name, arg2_val)        \
543   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                          \
544       TRACE_EVENT_PHASE_SAMPLE, category_group, name, 0, thread_id, timestamp, \
545       TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val, arg2_name, arg2_val)
546 
547 // ASYNC_STEP_* APIs should be only used by legacy code. New code should
548 // consider using NESTABLE_ASYNC_* APIs to describe substeps within an async
549 // event.
550 // Records a single ASYNC_BEGIN event called "name" immediately, with 0, 1 or 2
551 // associated arguments. If the category is not enabled, then this
552 // does nothing.
553 // - category and name strings must have application lifetime (statics or
554 //   literals). They may not include " chars.
555 // - |id| is used to match the ASYNC_BEGIN event with the ASYNC_END event. ASYNC
556 //   events are considered to match if their category_group, name and id values
557 //   all match. |id| must either be a pointer or an integer value up to 64 bits.
558 //   If it's a pointer, the bits will be xored with a hash of the process ID so
559 //   that the same pointer on two different processes will not collide.
560 //
561 // An asynchronous operation can consist of multiple phases. The first phase is
562 // defined by the ASYNC_BEGIN calls. Additional phases can be defined using the
563 // ASYNC_STEP_INTO or ASYNC_STEP_PAST macros. The ASYNC_STEP_INTO macro will
564 // annotate the block following the call. The ASYNC_STEP_PAST macro will
565 // annotate the block prior to the call. Note that any particular event must use
566 // only STEP_INTO or STEP_PAST macros; they can not mix and match. When the
567 // operation completes, call ASYNC_END.
568 //
569 // An ASYNC trace typically occurs on a single thread (if not, they will only be
570 // drawn on the thread defined in the ASYNC_BEGIN event), but all events in that
571 // operation must use the same |name| and |id|. Each step can have its own
572 // args.
573 #define TRACE_EVENT_ASYNC_BEGIN0(category_group, name, id)        \
574   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_BEGIN, \
575                                    category_group, name, id,      \
576                                    TRACE_EVENT_FLAG_NONE)
577 #define TRACE_EVENT_ASYNC_BEGIN1(category_group, name, id, arg1_name, \
578                                  arg1_val)                            \
579   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_BEGIN,     \
580                                    category_group, name, id,          \
581                                    TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
582 #define TRACE_EVENT_ASYNC_BEGIN2(category_group, name, id, arg1_name, \
583                                  arg1_val, arg2_name, arg2_val)       \
584   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                   \
585       TRACE_EVENT_PHASE_ASYNC_BEGIN, category_group, name, id,        \
586       TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val, arg2_name, arg2_val)
587 #define TRACE_EVENT_COPY_ASYNC_BEGIN0(category_group, name, id)   \
588   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_BEGIN, \
589                                    category_group, name, id,      \
590                                    TRACE_EVENT_FLAG_COPY)
591 #define TRACE_EVENT_COPY_ASYNC_BEGIN1(category_group, name, id, arg1_name, \
592                                       arg1_val)                            \
593   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_BEGIN,          \
594                                    category_group, name, id,               \
595                                    TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val)
596 #define TRACE_EVENT_COPY_ASYNC_BEGIN2(category_group, name, id, arg1_name, \
597                                       arg1_val, arg2_name, arg2_val)       \
598   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                        \
599       TRACE_EVENT_PHASE_ASYNC_BEGIN, category_group, name, id,             \
600       TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val, arg2_name, arg2_val)
601 
602 // Similar to TRACE_EVENT_ASYNC_BEGINx but with a custom |at| timestamp
603 // provided.
604 #define TRACE_EVENT_ASYNC_BEGIN_WITH_TIMESTAMP0(category_group, name, id, \
605                                                 timestamp)                \
606   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                     \
607       TRACE_EVENT_PHASE_ASYNC_BEGIN, category_group, name, id,            \
608       TRACE_EVENT_API_CURRENT_THREAD_ID, timestamp, TRACE_EVENT_FLAG_NONE)
609 #define TRACE_EVENT_ASYNC_BEGIN_WITH_TIMESTAMP1(                           \
610     category_group, name, id, timestamp, arg1_name, arg1_val)              \
611   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                      \
612       TRACE_EVENT_PHASE_ASYNC_BEGIN, category_group, name, id,             \
613       TRACE_EVENT_API_CURRENT_THREAD_ID, timestamp, TRACE_EVENT_FLAG_NONE, \
614       arg1_name, arg1_val)
615 #define TRACE_EVENT_COPY_ASYNC_BEGIN_WITH_TIMESTAMP0(category_group, name, id, \
616                                                      timestamp)                \
617   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                          \
618       TRACE_EVENT_PHASE_ASYNC_BEGIN, category_group, name, id,                 \
619       TRACE_EVENT_API_CURRENT_THREAD_ID, timestamp, TRACE_EVENT_FLAG_COPY)
620 
621 // Records a single ASYNC_STEP_INTO event for |step| immediately. If the
622 // category is not enabled, then this does nothing. The |name| and |id| must
623 // match the ASYNC_BEGIN event above. The |step| param identifies this step
624 // within the async event. This should be called at the beginning of the next
625 // phase of an asynchronous operation. The ASYNC_BEGIN event must not have any
626 // ASYNC_STEP_PAST events.
627 #define TRACE_EVENT_ASYNC_STEP_INTO0(category_group, name, id, step)  \
628   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_STEP_INTO, \
629                                    category_group, name, id,          \
630                                    TRACE_EVENT_FLAG_NONE, "step", step)
631 #define TRACE_EVENT_ASYNC_STEP_INTO1(category_group, name, id, step, \
632                                      arg1_name, arg1_val)            \
633   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                  \
634       TRACE_EVENT_PHASE_ASYNC_STEP_INTO, category_group, name, id,   \
635       TRACE_EVENT_FLAG_NONE, "step", step, arg1_name, arg1_val)
636 
637 // Similar to TRACE_EVENT_ASYNC_STEP_INTOx but with a custom |at| timestamp
638 // provided.
639 #define TRACE_EVENT_ASYNC_STEP_INTO_WITH_TIMESTAMP0(category_group, name, id, \
640                                                     step, timestamp)          \
641   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                         \
642       TRACE_EVENT_PHASE_ASYNC_STEP_INTO, category_group, name, id,            \
643       TRACE_EVENT_API_CURRENT_THREAD_ID, timestamp, TRACE_EVENT_FLAG_NONE,    \
644       "step", step)
645 
646 // Records a single ASYNC_STEP_PAST event for |step| immediately. If the
647 // category is not enabled, then this does nothing. The |name| and |id| must
648 // match the ASYNC_BEGIN event above. The |step| param identifies this step
649 // within the async event. This should be called at the beginning of the next
650 // phase of an asynchronous operation. The ASYNC_BEGIN event must not have any
651 // ASYNC_STEP_INTO events.
652 #define TRACE_EVENT_ASYNC_STEP_PAST0(category_group, name, id, step)  \
653   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_STEP_PAST, \
654                                    category_group, name, id,          \
655                                    TRACE_EVENT_FLAG_NONE, "step", step)
656 #define TRACE_EVENT_ASYNC_STEP_PAST1(category_group, name, id, step, \
657                                      arg1_name, arg1_val)            \
658   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                  \
659       TRACE_EVENT_PHASE_ASYNC_STEP_PAST, category_group, name, id,   \
660       TRACE_EVENT_FLAG_NONE, "step", step, arg1_name, arg1_val)
661 
662 // Records a single ASYNC_END event for "name" immediately. If the category
663 // is not enabled, then this does nothing.
664 #define TRACE_EVENT_ASYNC_END0(category_group, name, id)        \
665   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_END, \
666                                    category_group, name, id,    \
667                                    TRACE_EVENT_FLAG_NONE)
668 #define TRACE_EVENT_ASYNC_END1(category_group, name, id, arg1_name, arg1_val) \
669   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_END,               \
670                                    category_group, name, id,                  \
671                                    TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
672 #define TRACE_EVENT_ASYNC_END2(category_group, name, id, arg1_name, arg1_val, \
673                                arg2_name, arg2_val)                           \
674   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                           \
675       TRACE_EVENT_PHASE_ASYNC_END, category_group, name, id,                  \
676       TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val, arg2_name, arg2_val)
677 #define TRACE_EVENT_COPY_ASYNC_END0(category_group, name, id)   \
678   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_END, \
679                                    category_group, name, id,    \
680                                    TRACE_EVENT_FLAG_COPY)
681 #define TRACE_EVENT_COPY_ASYNC_END1(category_group, name, id, arg1_name, \
682                                     arg1_val)                            \
683   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_ASYNC_END,          \
684                                    category_group, name, id,             \
685                                    TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val)
686 #define TRACE_EVENT_COPY_ASYNC_END2(category_group, name, id, arg1_name, \
687                                     arg1_val, arg2_name, arg2_val)       \
688   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                      \
689       TRACE_EVENT_PHASE_ASYNC_END, category_group, name, id,             \
690       TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val, arg2_name, arg2_val)
691 
692 // Similar to TRACE_EVENT_ASYNC_ENDx but with a custom |at| timestamp provided.
693 #define TRACE_EVENT_ASYNC_END_WITH_TIMESTAMP0(category_group, name, id, \
694                                               timestamp)                \
695   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                   \
696       TRACE_EVENT_PHASE_ASYNC_END, category_group, name, id,            \
697       TRACE_EVENT_API_CURRENT_THREAD_ID, timestamp, TRACE_EVENT_FLAG_NONE)
698 #define TRACE_EVENT_ASYNC_END_WITH_TIMESTAMP1(category_group, name, id,       \
699                                               timestamp, arg1_name, arg1_val) \
700   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                         \
701       TRACE_EVENT_PHASE_ASYNC_END, category_group, name, id,                  \
702       TRACE_EVENT_API_CURRENT_THREAD_ID, timestamp, TRACE_EVENT_FLAG_NONE,    \
703       arg1_name, arg1_val)
704 
705 // NESTABLE_ASYNC_* APIs are used to describe an async operation, which can
706 // be nested within a NESTABLE_ASYNC event and/or have inner NESTABLE_ASYNC
707 // events.
708 // - category and name strings must have application lifetime (statics or
709 //   literals). They may not include " chars.
710 // - A pair of NESTABLE_ASYNC_BEGIN event and NESTABLE_ASYNC_END event is
711 //   considered as a match if their category_group, name and id all match.
712 // - |id| must either be a pointer or an integer value up to 64 bits.
713 //   If it's a pointer, the bits will be xored with a hash of the process ID so
714 //   that the same pointer on two different processes will not collide.
715 // - |id| is used to match a child NESTABLE_ASYNC event with its parent
716 //   NESTABLE_ASYNC event. Therefore, events in the same nested event tree must
717 //   be logged using the same id and category_group.
718 //
719 // Unmatched NESTABLE_ASYNC_END event will be parsed as an event that starts
720 // at the first NESTABLE_ASYNC event of that id, and unmatched
721 // NESTABLE_ASYNC_BEGIN event will be parsed as an event that ends at the last
722 // NESTABLE_ASYNC event of that id. Corresponding warning messages for
723 // unmatched events will be shown in the analysis view.
724 
725 // Records a single NESTABLE_ASYNC_BEGIN event called "name" immediately, with
726 // 0, 1 or 2 associated arguments. If the category is not enabled, then this
727 // does nothing.
728 #define TRACE_EVENT_NESTABLE_ASYNC_BEGIN0(category_group, name, id)        \
729   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_NESTABLE_ASYNC_BEGIN, \
730                                    category_group, name, id,               \
731                                    TRACE_EVENT_FLAG_NONE)
732 #define TRACE_EVENT_NESTABLE_ASYNC_BEGIN1(category_group, name, id, arg1_name, \
733                                           arg1_val)                            \
734   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_NESTABLE_ASYNC_BEGIN,     \
735                                    category_group, name, id,                   \
736                                    TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
737 #define TRACE_EVENT_NESTABLE_ASYNC_BEGIN2(category_group, name, id, arg1_name, \
738                                           arg1_val, arg2_name, arg2_val)       \
739   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                            \
740       TRACE_EVENT_PHASE_NESTABLE_ASYNC_BEGIN, category_group, name, id,        \
741       TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val, arg2_name, arg2_val)
742 // Records a single NESTABLE_ASYNC_END event called "name" immediately, with 0
743 // or 2 associated arguments. If the category is not enabled, then this does
744 // nothing.
745 #define TRACE_EVENT_NESTABLE_ASYNC_END0(category_group, name, id)        \
746   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_NESTABLE_ASYNC_END, \
747                                    category_group, name, id,             \
748                                    TRACE_EVENT_FLAG_NONE)
749 // Records a single NESTABLE_ASYNC_END event called "name" immediately, with 1
750 // associated argument. If the category is not enabled, then this does nothing.
751 #define TRACE_EVENT_NESTABLE_ASYNC_END1(category_group, name, id, arg1_name, \
752                                         arg1_val)                            \
753   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_NESTABLE_ASYNC_END,     \
754                                    category_group, name, id,                 \
755                                    TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
756 #define TRACE_EVENT_NESTABLE_ASYNC_END2(category_group, name, id, arg1_name, \
757                                         arg1_val, arg2_name, arg2_val)       \
758   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                          \
759       TRACE_EVENT_PHASE_NESTABLE_ASYNC_END, category_group, name, id,        \
760       TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val, arg2_name, arg2_val)
761 
762 // Records a single NESTABLE_ASYNC_INSTANT event called "name" immediately,
763 // with one associated argument. If the category is not enabled, then this
764 // does nothing.
765 #define TRACE_EVENT_NESTABLE_ASYNC_INSTANT1(category_group, name, id,        \
766                                             arg1_name, arg1_val)             \
767   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_NESTABLE_ASYNC_INSTANT, \
768                                    category_group, name, id,                 \
769                                    TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
770 // Records a single NESTABLE_ASYNC_INSTANT event called "name" immediately,
771 // with 2 associated arguments. If the category is not enabled, then this
772 // does nothing.
773 #define TRACE_EVENT_NESTABLE_ASYNC_INSTANT2(                              \
774     category_group, name, id, arg1_name, arg1_val, arg2_name, arg2_val)   \
775   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                       \
776       TRACE_EVENT_PHASE_NESTABLE_ASYNC_INSTANT, category_group, name, id, \
777       TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val, arg2_name, arg2_val)
778 
779 #define TRACE_EVENT_COPY_NESTABLE_ASYNC_BEGIN_WITH_TTS2(                       \
780     category_group, name, id, arg1_name, arg1_val, arg2_name, arg2_val)        \
781   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                            \
782       TRACE_EVENT_PHASE_NESTABLE_ASYNC_BEGIN, category_group, name, id,        \
783       TRACE_EVENT_FLAG_ASYNC_TTS | TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val, \
784       arg2_name, arg2_val)
785 #define TRACE_EVENT_COPY_NESTABLE_ASYNC_END_WITH_TTS2(                         \
786     category_group, name, id, arg1_name, arg1_val, arg2_name, arg2_val)        \
787   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                            \
788       TRACE_EVENT_PHASE_NESTABLE_ASYNC_END, category_group, name, id,          \
789       TRACE_EVENT_FLAG_ASYNC_TTS | TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val, \
790       arg2_name, arg2_val)
791 
792 // Similar to TRACE_EVENT_NESTABLE_ASYNC_{BEGIN,END}x but with a custom
793 // |timestamp| provided.
794 #define TRACE_EVENT_NESTABLE_ASYNC_BEGIN_WITH_TIMESTAMP0(category_group, name, \
795                                                          id, timestamp)        \
796   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                          \
797       TRACE_EVENT_PHASE_NESTABLE_ASYNC_BEGIN, category_group, name, id,        \
798       TRACE_EVENT_API_CURRENT_THREAD_ID, timestamp, TRACE_EVENT_FLAG_NONE)
799 
800 #define TRACE_EVENT_NESTABLE_ASYNC_END_WITH_TIMESTAMP0(category_group, name, \
801                                                        id, timestamp)        \
802   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                        \
803       TRACE_EVENT_PHASE_NESTABLE_ASYNC_END, category_group, name, id,        \
804       TRACE_EVENT_API_CURRENT_THREAD_ID, timestamp, TRACE_EVENT_FLAG_NONE)
805 
806 #define TRACE_EVENT_COPY_NESTABLE_ASYNC_BEGIN_WITH_TIMESTAMP0(          \
807     category_group, name, id, timestamp)                                \
808   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                   \
809       TRACE_EVENT_PHASE_NESTABLE_ASYNC_BEGIN, category_group, name, id, \
810       TRACE_EVENT_API_CURRENT_THREAD_ID, timestamp, TRACE_EVENT_FLAG_COPY)
811 #define TRACE_EVENT_COPY_NESTABLE_ASYNC_END_WITH_TIMESTAMP0(          \
812     category_group, name, id, timestamp)                              \
813   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                 \
814       TRACE_EVENT_PHASE_NESTABLE_ASYNC_END, category_group, name, id, \
815       TRACE_EVENT_API_CURRENT_THREAD_ID, timestamp, TRACE_EVENT_FLAG_COPY)
816 
817 // Records a single NESTABLE_ASYNC_INSTANT event called "name" immediately,
818 // with 2 associated arguments. If the category is not enabled, then this
819 // does nothing.
820 #define TRACE_EVENT_NESTABLE_ASYNC_INSTANT2(                              \
821     category_group, name, id, arg1_name, arg1_val, arg2_name, arg2_val)   \
822   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                       \
823       TRACE_EVENT_PHASE_NESTABLE_ASYNC_INSTANT, category_group, name, id, \
824       TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val, arg2_name, arg2_val)
825 
826 // Records a single FLOW_BEGIN event called "name" immediately, with 0, 1 or 2
827 // associated arguments. If the category is not enabled, then this
828 // does nothing.
829 // - category and name strings must have application lifetime (statics or
830 //   literals). They may not include " chars.
831 // - |id| is used to match the FLOW_BEGIN event with the FLOW_END event. FLOW
832 //   events are considered to match if their category_group, name and id values
833 //   all match. |id| must either be a pointer or an integer value up to 64 bits.
834 //   If it's a pointer, the bits will be xored with a hash of the process ID so
835 //   that the same pointer on two different processes will not collide.
836 // FLOW events are different from ASYNC events in how they are drawn by the
837 // tracing UI. A FLOW defines asynchronous data flow, such as posting a task
838 // (FLOW_BEGIN) and later executing that task (FLOW_END). Expect FLOWs to be
839 // drawn as lines or arrows from FLOW_BEGIN scopes to FLOW_END scopes. Similar
840 // to ASYNC, a FLOW can consist of multiple phases. The first phase is defined
841 // by the FLOW_BEGIN calls. Additional phases can be defined using the FLOW_STEP
842 // macros. When the operation completes, call FLOW_END. An async operation can
843 // span threads and processes, but all events in that operation must use the
844 // same |name| and |id|. Each event can have its own args.
845 #define TRACE_EVENT_FLOW_BEGIN0(category_group, name, id)        \
846   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_BEGIN, \
847                                    category_group, name, id,     \
848                                    TRACE_EVENT_FLAG_NONE)
849 #define TRACE_EVENT_FLOW_BEGIN1(category_group, name, id, arg1_name, arg1_val) \
850   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_BEGIN,               \
851                                    category_group, name, id,                   \
852                                    TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
853 #define TRACE_EVENT_FLOW_BEGIN2(category_group, name, id, arg1_name, arg1_val, \
854                                 arg2_name, arg2_val)                           \
855   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                            \
856       TRACE_EVENT_PHASE_FLOW_BEGIN, category_group, name, id,                  \
857       TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val, arg2_name, arg2_val)
858 #define TRACE_EVENT_COPY_FLOW_BEGIN0(category_group, name, id)   \
859   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_BEGIN, \
860                                    category_group, name, id,     \
861                                    TRACE_EVENT_FLAG_COPY)
862 #define TRACE_EVENT_COPY_FLOW_BEGIN1(category_group, name, id, arg1_name, \
863                                      arg1_val)                            \
864   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_BEGIN,          \
865                                    category_group, name, id,              \
866                                    TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val)
867 #define TRACE_EVENT_COPY_FLOW_BEGIN2(category_group, name, id, arg1_name, \
868                                      arg1_val, arg2_name, arg2_val)       \
869   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                       \
870       TRACE_EVENT_PHASE_FLOW_BEGIN, category_group, name, id,             \
871       TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val, arg2_name, arg2_val)
872 
873 // Records a single FLOW_STEP event for |step| immediately. If the category
874 // is not enabled, then this does nothing. The |name| and |id| must match the
875 // FLOW_BEGIN event above. The |step| param identifies this step within the
876 // async event. This should be called at the beginning of the next phase of an
877 // asynchronous operation.
878 #define TRACE_EVENT_FLOW_STEP0(category_group, name, id, step)  \
879   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_STEP, \
880                                    category_group, name, id,    \
881                                    TRACE_EVENT_FLAG_NONE, "step", step)
882 #define TRACE_EVENT_FLOW_STEP1(category_group, name, id, step, arg1_name, \
883                                arg1_val)                                  \
884   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                       \
885       TRACE_EVENT_PHASE_FLOW_STEP, category_group, name, id,              \
886       TRACE_EVENT_FLAG_NONE, "step", step, arg1_name, arg1_val)
887 #define TRACE_EVENT_COPY_FLOW_STEP0(category_group, name, id, step) \
888   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_STEP,     \
889                                    category_group, name, id,        \
890                                    TRACE_EVENT_FLAG_COPY, "step", step)
891 #define TRACE_EVENT_COPY_FLOW_STEP1(category_group, name, id, step, arg1_name, \
892                                     arg1_val)                                  \
893   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                            \
894       TRACE_EVENT_PHASE_FLOW_STEP, category_group, name, id,                   \
895       TRACE_EVENT_FLAG_COPY, "step", step, arg1_name, arg1_val)
896 
897 // Records a single FLOW_END event for "name" immediately. If the category
898 // is not enabled, then this does nothing.
899 #define TRACE_EVENT_FLOW_END0(category_group, name, id)                        \
900   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_END, category_group, \
901                                    name, id, TRACE_EVENT_FLAG_NONE)
902 #define TRACE_EVENT_FLOW_END_BIND_TO_ENCLOSING0(category_group, name, id)      \
903   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_END, category_group, \
904                                    name, id,                                   \
905                                    TRACE_EVENT_FLAG_BIND_TO_ENCLOSING)
906 #define TRACE_EVENT_FLOW_END1(category_group, name, id, arg1_name, arg1_val)   \
907   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_END, category_group, \
908                                    name, id, TRACE_EVENT_FLAG_NONE, arg1_name, \
909                                    arg1_val)
910 #define TRACE_EVENT_FLOW_END2(category_group, name, id, arg1_name, arg1_val,   \
911                               arg2_name, arg2_val)                             \
912   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_END, category_group, \
913                                    name, id, TRACE_EVENT_FLAG_NONE, arg1_name, \
914                                    arg1_val, arg2_name, arg2_val)
915 #define TRACE_EVENT_COPY_FLOW_END0(category_group, name, id)                   \
916   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_END, category_group, \
917                                    name, id, TRACE_EVENT_FLAG_COPY)
918 #define TRACE_EVENT_COPY_FLOW_END1(category_group, name, id, arg1_name,        \
919                                    arg1_val)                                   \
920   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_END, category_group, \
921                                    name, id, TRACE_EVENT_FLAG_COPY, arg1_name, \
922                                    arg1_val)
923 #define TRACE_EVENT_COPY_FLOW_END2(category_group, name, id, arg1_name,        \
924                                    arg1_val, arg2_name, arg2_val)              \
925   INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_FLOW_END, category_group, \
926                                    name, id, TRACE_EVENT_FLAG_COPY, arg1_name, \
927                                    arg1_val, arg2_name, arg2_val)
928 
929 // Records a clock sync event.
930 #define TRACE_EVENT_CLOCK_SYNC_RECEIVER(sync_id)                               \
931   INTERNAL_TRACE_EVENT_ADD(                                                    \
932       TRACE_EVENT_PHASE_CLOCK_SYNC, "__metadata", "clock_sync",                \
933       TRACE_EVENT_FLAG_NONE, "sync_id", sync_id)
934 #define TRACE_EVENT_CLOCK_SYNC_ISSUER(sync_id, issue_ts, issue_end_ts)         \
935   INTERNAL_TRACE_EVENT_ADD_WITH_TIMESTAMP(                                     \
936       TRACE_EVENT_PHASE_CLOCK_SYNC, "__metadata", "clock_sync",                \
937       issue_end_ts.ToInternalValue(), TRACE_EVENT_FLAG_NONE,                   \
938       "sync_id", sync_id, "issue_ts", issue_ts.ToInternalValue())
939 
940 // Macros to track the life time and value of arbitrary client objects.
941 // See also TraceTrackableObject.
942 #define TRACE_EVENT_OBJECT_CREATED_WITH_ID(category_group, name, id) \
943   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                  \
944       TRACE_EVENT_PHASE_CREATE_OBJECT, category_group, name,         \
945       TRACE_ID_DONT_MANGLE(id), TRACE_EVENT_FLAG_NONE)
946 
947 #define TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(category_group, name, id, \
948                                             snapshot)                 \
949   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                   \
950       TRACE_EVENT_PHASE_SNAPSHOT_OBJECT, category_group, name,        \
951       TRACE_ID_DONT_MANGLE(id), TRACE_EVENT_FLAG_NONE, "snapshot", snapshot)
952 
953 #define TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID_AND_TIMESTAMP(                    \
954     category_group, name, id, timestamp, snapshot)                            \
955   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                         \
956       TRACE_EVENT_PHASE_SNAPSHOT_OBJECT, category_group, name,                \
957       TRACE_ID_DONT_MANGLE(id), TRACE_EVENT_API_CURRENT_THREAD_ID, timestamp, \
958       TRACE_EVENT_FLAG_NONE, "snapshot", snapshot)
959 
960 #define TRACE_EVENT_OBJECT_DELETED_WITH_ID(category_group, name, id) \
961   INTERNAL_TRACE_EVENT_ADD_WITH_ID(                                  \
962       TRACE_EVENT_PHASE_DELETE_OBJECT, category_group, name,         \
963       TRACE_ID_DONT_MANGLE(id), TRACE_EVENT_FLAG_NONE)
964 
965 // Macro to efficiently determine if a given category group is enabled.
966 #define TRACE_EVENT_CATEGORY_GROUP_ENABLED(category_group, ret)             \
967   do {                                                                      \
968     INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group);                 \
969     if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE()) { \
970       *ret = true;                                                          \
971     } else {                                                                \
972       *ret = false;                                                         \
973     }                                                                       \
974   } while (0)
975 
976 // Macro to explicitly warm up a given category group. This could be useful in
977 // cases where we want to initialize a category group before any trace events
978 // for that category group is reported. For example, to have a category group
979 // always show up in the "record categories" list for manually selecting
980 // settings in about://tracing.
981 #define TRACE_EVENT_WARMUP_CATEGORY(category_group) \
982   INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group)
983 
984 // Macro to efficiently determine, through polling, if a new trace has begun.
985 #define TRACE_EVENT_IS_NEW_TRACE(ret)                                      \
986   do {                                                                     \
987     static int INTERNAL_TRACE_EVENT_UID(lastRecordingNumber) = 0;          \
988     int num_traces_recorded = TRACE_EVENT_API_GET_NUM_TRACES_RECORDED();   \
989     if (num_traces_recorded != -1 &&                                       \
990         num_traces_recorded !=                                             \
991             INTERNAL_TRACE_EVENT_UID(lastRecordingNumber)) {               \
992       INTERNAL_TRACE_EVENT_UID(lastRecordingNumber) = num_traces_recorded; \
993       *ret = true;                                                         \
994     } else {                                                               \
995       *ret = false;                                                        \
996     }                                                                      \
997   } while (0)
998 
999 // Notes regarding the following definitions:
1000 // New values can be added and propagated to third party libraries, but existing
1001 // definitions must never be changed, because third party libraries may use old
1002 // definitions.
1003 
1004 // Phase indicates the nature of an event entry. E.g. part of a begin/end pair.
1005 #define TRACE_EVENT_PHASE_BEGIN ('B')
1006 #define TRACE_EVENT_PHASE_END ('E')
1007 #define TRACE_EVENT_PHASE_COMPLETE ('X')
1008 #define TRACE_EVENT_PHASE_INSTANT ('I')
1009 #define TRACE_EVENT_PHASE_ASYNC_BEGIN ('S')
1010 #define TRACE_EVENT_PHASE_ASYNC_STEP_INTO ('T')
1011 #define TRACE_EVENT_PHASE_ASYNC_STEP_PAST ('p')
1012 #define TRACE_EVENT_PHASE_ASYNC_END ('F')
1013 #define TRACE_EVENT_PHASE_NESTABLE_ASYNC_BEGIN ('b')
1014 #define TRACE_EVENT_PHASE_NESTABLE_ASYNC_END ('e')
1015 #define TRACE_EVENT_PHASE_NESTABLE_ASYNC_INSTANT ('n')
1016 #define TRACE_EVENT_PHASE_FLOW_BEGIN ('s')
1017 #define TRACE_EVENT_PHASE_FLOW_STEP ('t')
1018 #define TRACE_EVENT_PHASE_FLOW_END ('f')
1019 #define TRACE_EVENT_PHASE_METADATA ('M')
1020 #define TRACE_EVENT_PHASE_COUNTER ('C')
1021 #define TRACE_EVENT_PHASE_SAMPLE ('P')
1022 #define TRACE_EVENT_PHASE_CREATE_OBJECT ('N')
1023 #define TRACE_EVENT_PHASE_SNAPSHOT_OBJECT ('O')
1024 #define TRACE_EVENT_PHASE_DELETE_OBJECT ('D')
1025 #define TRACE_EVENT_PHASE_MEMORY_DUMP ('v')
1026 #define TRACE_EVENT_PHASE_MARK ('R')
1027 #define TRACE_EVENT_PHASE_CLOCK_SYNC ('c')
1028 
1029 // Flags for changing the behavior of TRACE_EVENT_API_ADD_TRACE_EVENT.
1030 #define TRACE_EVENT_FLAG_NONE (static_cast<unsigned int>(0))
1031 #define TRACE_EVENT_FLAG_COPY (static_cast<unsigned int>(1 << 0))
1032 #define TRACE_EVENT_FLAG_HAS_ID (static_cast<unsigned int>(1 << 1))
1033 #define TRACE_EVENT_FLAG_MANGLE_ID (static_cast<unsigned int>(1 << 2))
1034 #define TRACE_EVENT_FLAG_SCOPE_OFFSET (static_cast<unsigned int>(1 << 3))
1035 #define TRACE_EVENT_FLAG_SCOPE_EXTRA (static_cast<unsigned int>(1 << 4))
1036 #define TRACE_EVENT_FLAG_EXPLICIT_TIMESTAMP (static_cast<unsigned int>(1 << 5))
1037 #define TRACE_EVENT_FLAG_ASYNC_TTS (static_cast<unsigned int>(1 << 6))
1038 #define TRACE_EVENT_FLAG_BIND_TO_ENCLOSING (static_cast<unsigned int>(1 << 7))
1039 #define TRACE_EVENT_FLAG_FLOW_IN (static_cast<unsigned int>(1 << 8))
1040 #define TRACE_EVENT_FLAG_FLOW_OUT (static_cast<unsigned int>(1 << 9))
1041 #define TRACE_EVENT_FLAG_HAS_CONTEXT_ID (static_cast<unsigned int>(1 << 10))
1042 #define TRACE_EVENT_FLAG_HAS_PROCESS_ID (static_cast<unsigned int>(1 << 11))
1043 
1044 #define TRACE_EVENT_FLAG_SCOPE_MASK                          \
1045   (static_cast<unsigned int>(TRACE_EVENT_FLAG_SCOPE_OFFSET | \
1046                              TRACE_EVENT_FLAG_SCOPE_EXTRA))
1047 
1048 // Type values for identifying types in the TraceValue union.
1049 #define TRACE_VALUE_TYPE_BOOL (static_cast<unsigned char>(1))
1050 #define TRACE_VALUE_TYPE_UINT (static_cast<unsigned char>(2))
1051 #define TRACE_VALUE_TYPE_INT (static_cast<unsigned char>(3))
1052 #define TRACE_VALUE_TYPE_DOUBLE (static_cast<unsigned char>(4))
1053 #define TRACE_VALUE_TYPE_POINTER (static_cast<unsigned char>(5))
1054 #define TRACE_VALUE_TYPE_STRING (static_cast<unsigned char>(6))
1055 #define TRACE_VALUE_TYPE_COPY_STRING (static_cast<unsigned char>(7))
1056 #define TRACE_VALUE_TYPE_CONVERTABLE (static_cast<unsigned char>(8))
1057 
1058 // Enum reflecting the scope of an INSTANT event. Must fit within
1059 // TRACE_EVENT_FLAG_SCOPE_MASK.
1060 #define TRACE_EVENT_SCOPE_GLOBAL (static_cast<unsigned char>(0 << 3))
1061 #define TRACE_EVENT_SCOPE_PROCESS (static_cast<unsigned char>(1 << 3))
1062 #define TRACE_EVENT_SCOPE_THREAD (static_cast<unsigned char>(2 << 3))
1063 
1064 #define TRACE_EVENT_SCOPE_NAME_GLOBAL ('g')
1065 #define TRACE_EVENT_SCOPE_NAME_PROCESS ('p')
1066 #define TRACE_EVENT_SCOPE_NAME_THREAD ('t')
1067